1. Field of the Invention
The present invention relates generally to tires for vehicles and, more particularly, to a non-pneumatic tire which can provide handling performance similar to that of a pneumatic tire despite using no pneumatic pressure, and which can structurally withstand the weight of a vehicle.
2. Description of the Related Art
Generally, tires for vehicles are classified into radial tires, bias tires, solid tires, etc. according to the structure. Most vehicles, including passenger cars, with the exception of special purpose vehicles, use radial tires, that is, pneumatic tires. However, the structure of such a pneumatic tire is complex, and a comparatively large number of manufacturing processes, typically eight steps, is required. As a result of an increase in the number of manufacturing processes, a discharge amount of harmful substances is also increased. Furthermore, because the pneumatic pressure of the tire positively influences the performance and safety of the pneumatic tire, it must be frequently checked, thus inconveniencing a user in terms of maintenance. Moreover, there is the possibility of the tire being damaged by an external substance that may pierce the tire or apply an impact to it while the vehicle is moving.
Meanwhile, unlike the pneumatic tire, a non-pneumatic tire makes it possible to simplify the material and the manufacturing process, whereby the production cost can be markedly reduced. In addition, the non-pneumatic tire has an improved structure and can be manufactured by an improved process which can reduce energy consumption and the amount of harmful substances discharged. Above all, the non-pneumatic tire can avoid problems which may be caused by insufficient pneumatic pressure in the conventional tire. Furthermore, the non-pneumatic tire can prevent a standing wave phenomenon which occurs in the pneumatic tire. Moreover, the non-pneumatic tire can markedly improve characteristics of resistance to rolling.
The non-pneumatic tire has a completely different structure from the pneumatic tire. Unlike the pneumatic tire, because the non-pneumatic tire is configured such that no compressed air is used, there is no possibility of an accident occurring while the vehicle is moving that is attributable to a shortage of pneumatic pressure or a flat tire.
Such non-pneumatic tires have existed and been produced by conventional techniques. For example, wagon wheels or bicycle wheels were used many years ago. These days, a technique, in which a plurality of support members including multi-layered staples support the load of a tire, was proposed in Korean Patent Laid-open Publication No. 2006-0051513. Further, in a technique proposed in Korean Patent Laid-open Publication No. 2008-0038274, a non-pneumatic tire includes a main body which is made of elastic material, a circumferential-extending crown part which functions as a tread, and an extension sidewall which is coupled to the crown part. In addition, a non-pneumatic tire, which includes an annular band that supports the load of the tire, and a plurality of web spokes that supports the load between the tire and a wheel or a hub with tension, was proposed in Korean Patent Laid-open Publication No. 2004-0027984.
In the case of the non-pneumatic tire including the spokes, it was introduced that the load applied to the tire is supported by the tensile force of the spokes. In this case, a reinforcing member is provided between the web spokes and the tread that comes into contact with the ground so that it can support the weight of the vehicle and conduct the same function as pneumatic pressure in the pneumatic tire. For instance, a structural support type non-pneumatic wheel having a continuous loop reinforcement assembly was proposed in Korean Patent Application No. 2012-7023435. In this technique, a spiral-coiled reinforcing member was introduced.
However, the support force of the spiral-coiled reinforcing member of the conventional technique that supports the weight of the vehicle is limited. This causes many problems such as deterioration in handling performance, ride comfort and the durability of a web spoke part.